Vertical tube evaporator



M r h 1 5 H. E. JACOBY ET AL 2,544,885

VERTICAL TUBE EVAPORATOR Filed Feb. 27, 1946 2 Sheets-Sheet 1 INVENTORATTOR EYS March 13, 1951 H. E. JACOBY ETAL VERTICAL TUBE EVAPQRATOR 2Sheets-Sheet 2 Filed Feb. 27, 1946 IL wm UN? INVENTOR Harold E. Jacoby'BY CheriesPzVz'Zen Qa ATT Patented Mar. 13, 1951 VERTICAL TUBEEVAPORATOR Harold E. J acoby, Brooklyn, and Charles P. Nilan, PointLookout, N. Y., assignors to General American TransportationCorporation, Chicago, 111., a corporation of New York ApplicationFebruary 27, 1946, Serial No. 650,468

6 Claims. (Cl. 159-27) This invention relates to evaporators and moreparticularly to a novel unitary construction of evaporator body adaptedto be incorporated in a multiple effect evaporating system.

A multiple effect evaporator commonly comprises two or more evaporatorbodies each of which includes a heating element and a vapor separatorchamber, the evaporator bodies being so interconnected that the vaporsfrom one body or effect are fed to the heating element of the nexteffect. In evaporators of the type with which the present invention isconcerned the liquor (i. e., any liquid which is to be evaporated) isheated within a heating element, usually of tubular construction, bytransfer of heat from vapors outside the tubes. Movement of the liquorthrough the tubes is achieved either by maintenance of a suitablehydrostatic head of the liquor or by pumping the liquor through thetubes or by utilizing the thermosiphon action induced by heat transferfrom the outside of the tubes to the liquor within the tubes or by acombination of two or more of these methods.

In addition to the evaporator body itself, it is the usual practice toprovide a device known as an entrainment separator for removing anyentrained liquor from the vapors formed in the evaporator. This iscommonly done in a separator chamber which drains the separated liquorback to the evaporator. It is also known to provide one or more flashchambers through which steam condensate or superheated liquor arepassed. In these flash chambers the hot liquor or condensate is exposedto a lower pressure at which its own heat serves to produce spontaneousvaporization or flashing of a part of the liquid and thereby to avoidpossible waste of such heat. Each one of the evaporating units atdifferent pressures is called an effect. Since the steam or vaporpressure in successive effects decreases,

- condensate from any effect except the last effect contains heat thatmay be converted into steam and used as a heating medium in a successiveeffect. By causing the steam condensate from one effect to flow into aflash chamber maintained at the lower pressure of another effect, aportion of the condensate vaporizes and may be used as a heating mediumin the latter effect. In somewhat similar fashion, in cases where theliquor fed to the evaporator is superheated with respect to theconditions existing in the effect into which the liquor is to beintroduced, the liquor may be passed through a liquor flash chamber topermit flash evaporation of a portion thereof.

It is an object of the present invention to provide an improvedevaporator body construction wherein the evaporator body contains notonly the usual heating element and vapor separator chamber but may alsocontain an entrainment separator or a condensate flash chamber or aliquor flash chamber or any two or all three of these additionalelements. By incorporating the entrainment separator and flash chambersin the evaporator body in accordance with the present invention acompletely self-contained and selfsupporting unit may be achieved. Sucha selfcontained and self-supporting unit eliminates the necessity ofexpensive structural steel supports such as have been previously usedfor sup- "porting the different elements of an evaporator.

The work involved in installing an evaporator system and the cost ofinstallation are thus reduced materially, since apart from accessories,such as pipes, pumps and the like only a single unit of the equipmentneed be handled for each effect'that is to be installed. Further thecompactness of an evaporator incorporating the present constructionreduces the space require-' that these arenot intended to be exhaustiveor limiting of the invention. On the contrary, we are giving these asillustrations and are giving herewith explanations in order fully toacquaint others skilled in the artwith our invention and the principlesthereof and a suitable manner of its application in practical use, sothat others skilled in the art may be enabled to modify the inventionand to adapt it and apply it in numerous forms each as may be bestsuited to the requirement of a particular use.

The many objects and advantages of the present construction may best beappreciated by reference to the accompanying drawings which illustratean evaporator incorporating a preferred embodiment of the invention andwherein:

Figure 1 is a vertical section through the evaporator showing thearrangement of theprincipal elements within the evaporator body; and

Figure 2 is a diagrammatic illustration of the manner in whichevaporator bodies incorporating the present invention may beinterconnected in a multiple effect evaporating system.

Referring to the drawings, and more particular ly to Figure 1, thenumeral generally designates an evaporator body comprising a cylindricalouter shell or casing ii that encloses a vapor separator chamber 2, aheating element comprising the tube bundle [4, an entrainment separatorchamber [6, a liquor flash chamber I8 and a condensate flash chamber 20.(Relatively few tubes are shown in the tube bundle on. the drawing toavoid confusion of lines; but any required numbermay be used in accordwith accepted engineering principles.) This tube bundle 14 comprises aplurality of tubes that are mounted in the usual manner in an upper tubesheet 22 and a lower tube sheet 24. The lower tube sheet 24 is mountedbetween a flanged condensate receiving section 26 of the evaporator bodyit and a flanged ring 28. Closure of the lower end of easing H isprovided by a flanged cap section 38 connected to the flanged ring 28 insuch manner that it may be easily removed to provide ready access to thetubes of the tube bundle Hi. the upper end of casing H a cap 31 isprovided that may be removed to permit access to the vapor separatorchamber l2 and upper tube sheet 22.

The upper tube sheet 22 is supported by an annular ring 32 fixed to thecasing II. An expansion joint 34 is provided between the tube sheet 22and supporting ring 32 to permit necessary expansion of the tubes of thetube bundle i l. The tube sheet 22, expansion joint 36 and ring 32effectively comprise a wall of the vapor separator chamber I2.

Surrounding the upper and central portions of the tube bundle Hi thereis a cylindrical partition 38 that is supported from the vertical wallof casing i I by an upper annular ring 38 and lower annular ring 48. Thecylindrical partition 38 and annular ring 33 cooperate with the verticalwall of the casing H to define the annular opentopped entrainmentseparator chamber l5 into which the vapors from a previous efiect may beintroduced tangentially through a pipe 42. The construction is such thatthe vapors entering through the pipe G2 are whirled around in thechamber I6 and non-gaseous constituents contained in the vapors areremoved. The separated liquor is removed from the chamber it through aconnection 44 and the vapors that have been freed from entrained liquorfiow over the top of the cylindrical partition 36 and thence downwardlyin contact with the tubes of tube bundle As previously pointed out, theliquor to be evaporated may be superheated and it is desirable that aflash chamber be provided for removal of this superheat beforesubsequent utilization. The annular rings 38 and All, the lower portionof cylindrical partition .35 and the vertical wall of casing l define anenclosed annular liquor flash chamber [8 that may be used for thispurpose. Liquor may enter the chamber 18 through a connection 46 andleave the chamber through a connection 48. Within the chamber 18 thepressure is maintained at such a value that a suificient portion of theentering liquor flashes into steam to de-superheat the liquor. Theevolved vapor may be withdrawn through a connection 50 near the top ofthe chamber l8.

Liquor leaving the chamber 18 through connection 48 may be conducted bya pipe (not shown in Figure 1) to a connection 52 in the flanged ringsection 28 of the evaporator body. The liquor thus introduced passesupwardly through the tubes of tube bundle M where it is heated bycondensation outside the tubes of either steam or vapors from apreceding effect. As the liquor passes through the tubes, andevaporation of the liquor occurs, the velocity of the mixture 01 liquorand vapor increases, and the vaporliquor mixture leaving the upper endof the tubes of tube bundle l4 impinges upon a curved bailie plate 54that is mounted in the path of the vaporliquor mixture to deflect themixture downwardly. Separation of the vapor from the liquor in thismixture occurs within the vapor separator chamber 12 and the vaporsleave the evaporator body through an outlet connection 56 near the topof the vapor separator chamber. The liquor thus separated may bewithdrawn from the vapor separator chamber through a connection 53.

To utilize the superheat that may be present in the condensate from aprevious effect a condensate flash chamber 20 is provided near thebottom of body I9. Surrounding the lower portion of tube bundle Hi thereis a cylindrical partition 63 that cooperates with the casing wall H todefine the open-topped annular condensate flash chamber 2e. Condensatefrom a previous efiect may enter the chamber 28 through a connection 52and vapors flashing from the condensate pass over the top of cylindricalpartition 55 into contact with the tube bundle is. The partition 58forms a baille that effectively prevents the entering condensate fromimpinging directly on the tubes of tube bundle lil. De-superheatedcondensate flows through a'hole 6 3 in the partition 68 thence downwardinto the condensate receiving section 25 and out of the evaporator bodythrough condensate outlet connection 66.

The vapors entering the evaporator body through the inlet connection 42normally contain a small proportion of non-condensible vapor that tendsto collect in the central and lower portions of the tube bundle is andmeans are provided for removing this non-condensible vapor. Centrallylocated in the tube bundle Hi there is a tube 68 that extends from theupper tube sheet 22 down through the center of tube bundle it, throughthe lower tube sheet 24 and then out through the wall of flanged ring28. Near its lower end tube 68 is provided with a plurality of holes '58through which non-condensible vapor that collects in the lower centralportion of the tube bundle may pass to the interior of tube 58 and bewithdrawn from the evaporator body, e. g., by an ejector or pump or byventing, depending upon the pressure. It is apparent that only the lowerportion of tube 68 is effective in withdrawing non-condensible vaporsfrom the evaporator body but it is desirable that the tube 58 extend tothe upper tube sheet 22 so that the symmetry of the tube bundle may bepreserved and channelling of the steam or'vapors avoided. If the tube 63did not extend upwardly to the upper tube sheet, the resulting openingin the center 01 the tube bundle would provide a bypass through whichsteam .or hot vapors might flow without coming in contact with theheating surfaces of the tube bundle. This feature of the presentevaporator is described more fully in copending application Serial No.712,810 filed on November 29, 1946.

The evaporator body ill may be supported in any suitable manner. In thepresent embodiment the casing H and its associated structure issupported on a cylindrical skirt 12 that is fixed to the casing in anysuitable manner, such as by welding, and extends from the bottom of thecasing to the iioor or other structure on which the evaporator body ismounted. An opening 74 is provided in the skirt I2 to permit access tothe lower portion of the evaporator body. It is apparent that othersupporting means such as structural steel legs in the form of T-beams orI-beams may be used in place of the skirt 12.

The evaporator of the present invention is particularly adapted for usein multiple effect evaporating systems and the manner in which a numberof evaporator bodies incorporating the present invention can beinterconnected in a multiple effect system is illustrateddiagrammatically in Figure 2 of the drawings. Referring to Figure 2, thenumerals I68, I82 and I04 designate the several evaporator eifectshaving bodies Illa and IE1) generally similar to the evaporator body Illshown in Figure l. Superheated liquor to be evaporated is fed to theliquor fiash chamber Ida of evaporator body Iuc of the final effect itthrough a pipe I66, and the superheat removed by partial vaporization ofthe liquor. From the liquor flash chamber of body Idc the liquor flowsthrough pipe I98 to the bottom of the evaporator body Ito, enters theevaporator body through the connection 52a and then flows up through thetube bundle of this evaporator body to the vapor separator chamber I20wherein the liquor and associated vapor are separated. The liquor leavesthe evaporator body Iiic through pipe H9 and is transferred by means or"transfer pump H2 and pipe H4 to the bottom of evaporator body Ifib ofthe effect I02.

Since the liquor at this stage contains no superheat it is unnecessarythat the evaporator body Iiib be provided with a liquor flash chamber.The entering liquor passes up through the tube bundle in the evaporatorbody Iiib of effect I62, the portion of the liquor vaporized within thetubes being separated from the liquor in its vapor separator chamberI221. The separated liquor leaves body Iilb through pipe HM and istransferred by transfer pump I I2a and pipe I Ida to the bottom of theevaporator body Illa of the first effect I08.

A further quantity of the liquor is vaporized within the tubes ofevaporator body Illa and the resulting vapor-liquor mixture is separatedin its vapor separator chamber IZa. Concentrated liquor leaves the bodyIlla through the outlet pipe I22.

Vapors from the vapor separator chamber I2a of body lea are conductedthrough a vapor pipe I26 to the entrainment separator ISb of the bodyilib wherein entrained liquor is separated from the vapors. These vaporspass over the rim of the cylindrical baiiie 38b into contact with thetube bundle in the body Iflb and the separated liquor flows through pipeI2! into the concentrated liquor pipe I22.

Vapors from the vapor separator chamber I2b of the body Itb areconducted through a pipe 52 m to the entrainment separator of body Iflcof the next effect I65 where entrained liquor is separated from thesevapors in the same manner as before. The vapors then pass into contactwith the tube bundle of body I80 and the separated liquor is withdrawnthrough pipe I 2Ia and flows into pipe II Ba and thence through pump HMand pipe I I l to the bottom of body Ilia.

Vapors from the vapor separator chamber of the body lilcpass through atangential vane, or other conventional, entrainment separator I36 on thetop of body We and thence through vapor pipe I32 to a barometric orother condenser (not shown).

Vapors evolved in the liquor flash chamber I8a of the body Iiic areremoved near the top of the liquor flash chamber and pass through pipeI34 to the separating chamber I20 or directly to the vapor pipe I32. Ifdesired, a pressure differential may be maintained by a restriction orcheck valve (not shown) in the connecting pipe I34 Steam is supplied tothe system and particularly to evaporator body I011. through a, steaminlet pipe I36. The steam flows into contact with the tube bundle ofbody Illa and is-condensed on the outer surface of the tubes, thecondensate being collected near the bottom of the body Ifla and removedthrough pipe I38. Since the condensate in thefirst eifect is free fromcontaminants that are sometimes present in the vapor of the liquor beingevaporated, it is desirable that the condensate from the first effect besegregated and not passed on to a subsequent effect where it would mixwith other vapor condensate. Any condensate collecting in the chamberIfia may be drained off through outlet Ma or an internal opening may beprovided through flange 38a to drain the condensate to the bottom of thetube bundle where it is drawn off from outlet 66 through pipe I38.

The condensate collecting at the bottom of evaporator body Iiib ofefiect IE2 is transferred through pipe I iii to the condensate flashchamber of body We. Since the steam, spaces I3 and Id of later effects,such as Iii l, are normally maintained at lower pressure than thecorresponding space in preceding eifects (in the triple effectevaporator shown), a portion of the condensate entering the condensateflash chamber 20 of the third effect Iii i will vaporize and pass intocontact with its tube bundle, The unvaporized condensate flows to thebottom of the body I where it mixes with condensate from the tube bundleof that body and the mixed condensate is withdrawn through a pipe I62 bya condensate transfer pump Hid.

From the foregoing description it is apparent that an evaporator bodyconstructed in accordance with the present invention may be effectivelyincorporated in a multiple efiect evaporating system to provide a numberof important advantages over previously proposed constructions. Theprincipal evaporator elements of each effect are so combined in acompact unitary structure as to provide a self-contained,self-supporting unit that may be conveniently handled duringinstallation. The self-supporting feature eliminates thenecessity forspecial structural steel supports and the expense incident to theerection of such supports. This self-supporting feature is particularlyadvantages where the evaporator is to be installed outside of a buildingand no building structure is available for supporting the evaporatorunit or units. The arrangement of the entrainment separator and flashchambers in the form of annular chambers surrounding the tube bundleresults in eiiicient utilization of the available space within theevaporator body and desired vapor flow parallel to the tubes of the tubebundle.

Further, the present construction provides flexi-bility in manufacture.Thus each of the chambers located adjacent the tube bundle, i. e., theentrainment separator, the liquor flash chamber and the condensateffiash chamber may' be omitted from or incorporated in a particularevaporator body with special advantages as desired :but withoutinterfering with the essentially self-contained and self-supportingcharacter of the structure. If .desired different portions of theevaporator unit, such as the vapor separator chamber, may be separatelyfabricated and connected by fianges or in another suitable manner tofacilitate shipment and erection.

We claim:

1. A unitary evaporator body adapted to be used in a multiple effectevaporating system for evaporating one :or more components of asolution, said evaporator body comprising upper and lower spaced tubesheets, a plurality of tubes mounted'at their ends in said tube sheetsto form a tube bundle, a casing substantially enclosing said tubebundle, said casing extending substantially above said upper tube sheetand having a closed upper end that defines with the upper portion of thecasing and the upper tube sheet a vapor separator chamber, cylindricalwall means surrounding said tube bundle and positioned close thereto, anannular partition extending from said wall means to said casing anddefining with said wall means and easing an annular entrainmentseparator chamber surrounding said tube bundle, said separator chamberbeing open at its top to communicate with the tubes of said tube bundle,a tangential inlet connection formed in that portion of the casing thatconstitutes the outer wall of said annular chamber and through which afiuid mixture may be tangentially introduced into said chamber forseparation, and an outlet connection formed in said casing near thebottom of said chamber for removal of separated liquid from saidseparator chamber and evaporator body, the diameter of the portion ofsaid casing that partially defines said annular chamber beingsufiiciently greater than the diameter of said wall means to provide anefficient separating space in said separator chamber.

2. A unitary evaporator body adapted to be used in a multiple effectevaporating system for evaporating one or more components of a solution,said evaporator body comprising upper and lower spaced tube sheets, aplurality of tubes mounted at their ends in said tube sheets to form atube bundle, a casing substantially enclosing said tube bundle, saidcasing extending substantially above said upper tube sheet and having aclosed upper end that defines with the upper portion of the casing andthe upper tube sheet a vapor separator chamber, cylindrical wall meanssurrounding said tube bundle and positioned close thereto, a firstannular partition extending from said wall means to said casing anddefining with said wall means and casing a first annular separatorchamber surrounding said tube bundle, said separator chamber being openat its top to communicate with the tubes of said ;tube bundle, atangential inlet connection formed in that portion of the casing thatconstitutes the outer wall of said annular chamber and through which afluid mixture may be tangentially introduced into said first chamber forseparation, an outlet connection formed in said casing near the bottomof said first annular chamber for removal of separated liquid from saidfirst annular chamher and evaporator body, a second partition betweensaid wall means and casing below said first partition and defining withsaid first partition casing and wall means a second annular 8 chamber,said :second annular chamber being provided with an :inletconnection-and a pair of outlet connections formed in that portion ofsaid casing that constitutes the outer wall of said second annularchamber, one of said pairof outlet connections being located near thetop of said second chamber and the other being located near the bottomof said second chamber, and the diameterof the portion of said casingpartially l defining said two annular chambers being sufficientlygreater than the diameter of said wall means to provide an efiioientseparating space in said annular separator chambers. 3. A unitaryevaporator body adapted to be 5 used in a multiple effect evaporatingsystem for evaporating one or more components of a solution, saidevaporator body comprising upper and lower spaced tube sheets, aplurality of tubes mounted at their ends in said tube sheets to form atube bundle, a casing substantially enclosing said tube bundle, saidcasing extending substantially above said upper tube sheet and having aclosed upper end that defines with the upper portion of the casing andthe upper tube sheet a vapor separator chamber, a first cylindrical wallgmember surrounding said tube bundle and positioned close thereto, anannular partition extending from said wall member to said casing anddefining with said first wall member and casing an annular entrainmentseparator chamber surrounding said tube bundle, said separator chamherbeing open at its top to communicate with the tubes of said tube bundle,a tangential inlet connection formed in the portion of the casing thatconstitutes the outer wall of said first annular chamber and throughwhich a fluid mixture may be tangentially introduced into said chamberfor separation, an outlet connection formed in said casing near thebottom of said chamber for re moval of separated liquid from said firstannular chamber and evaporator body, a second annular wall memberpositioned below said first wall member and cooperating with said casingto define a second annular chamber surrounding said tube bundle and openat its top to communicate with tubes of said tube bundle, said secondannular chamberhaving an inlet connection formed in its outer wall and adrain connection near the bottom thereof for removal of separatedliquid, the diameter of that portion of said casing defining said firstand second annular chambers being sufiiciently greater than the diameterof said wall members to provide an eificient separating space in saidtwo annular chambers.

4. A unitary evaporator body adapted to be used in a multiple efiectevaporating system for evaporating one or more components of a solution,said evaporator body comprising upper and lower spaced tube sheets, aplurality of tubes 69 mounted at their ends in said tube sheets to forma tube bundle, a casing substantially enclosing said tube bundle, saidcasing extending substantially above said upper tube sheet and having wa closed upper end that defines with the upper portion of said casingand the upper tube sheet a vapor separator chamber, cylindrical wallmeans surrounding said tube bundle and positioned close thereto, and aplurality of annular partitions extending from said wall means to 70said casing and defining with said well means and said casing threevertically spaced annular separator chambers surrounding said tubebundle, each of said annular chambers being provided with an inletconnection formed in said casing for admission of a fluid mixture to thechamber,

a first outlet near the top of said chamber for removal of separatedvapor therefrom and a second outlet near the bottom of said chamber forremoval of separated liquid therefrom.

5. An evaporator body according to claim 4 and wherein the upper andlower of said three annular chambers are open at the top to communicatewith the tubes of said tube bundle, the uppermost of said three annularchambers is provided with a tangential inlet connection, and thediameter of said casing is uniform throughout its height.

6. A unitary evaporator body adapted to be used in a multiple efiectevaporating system for evaporating one or more components of a solution,said evaporator body comprising upper and lower spaced tube sheets, aplurality of tubes mounted at their ends in said tube sheets to form atube bundle, a vertical cylindrical casing having a uniform diametersubstantially greater than the diameter of said tube bundle andsubstantially enclosing said tube bunde, said cylindrical casingextending substantially above said upper tube sheet and having a closedupper end that defines with the upper portion of the casing and theupper tube sheet a vapor separator chamber, cylindrical wall meanssurrounding said tube bundle and positioned close thereto, an annularpartition extending from said wall means to said 10 casing and definingwith said wall means and casing an annular separator chamber surroundingsaid tube bundle, said separator chamber being open at its top tocommunicate with the tubes of said tube bundle, a, tangential inletconnection formed in the portion of said casing that forms the outerwall of said annular chamber and through which a fluid mixture may beintroduced into said chamber for separation, and an outlet connectionformed in said casing near the bottom of said annular chamber forremoval of separated liquid therefrom, the diameter of said casing beingsufiiciently greater thanthe diameter of said wall means to provide anefiicient separating space in said separator chamber.

' HAROLD E. JACOBY.

CHARLES P. NILAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,735,980 Sadtler Nov. 19, 19291,750,306 Harris Mar. 11, 1930 1,864,349 Grover June 21, 1932 2,181,750Walker 1 Nov. 28, 1939

